1. Field of the Invention
This invention relates to logic circuits and, more specifically, to schottky logic circuit utilizing current mode logic.
2. Brief Description of the Prior Art
Prior art logic circuits are based upon certain trade-offs, depending upon the desired features. For example, ECL (emitter coupled logic) circuits are high speed. However, they suffer the disadvantage of requiring great parameter precision and stability for current sources which precision and stability is provided in the form voltage references, thereby necessitating a relatively large number of components. This problem is compounded due to the requirement that the voltage source change in a very specific manner due to temperature change. Such ECL circuits also have a relatively high power requirement in that they normally require a supply in excess of about four volts. On the other hand, STL (schottky transistor logic) type circuits have a small voltage swing due to different schottky diode voltages, however such circuits require very low RCS transistors and are therefore restricted to low power applications, hence are limited in operating speed.
It is clearly desirable to provide the speed of ECL circuits while utilizing fewer components and less power as well as providing such circuit with small voltage swing, but which has higher power capability and higher speed than the STL type circuits.